package com.liuyan.util;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

/**
 * Created by pc on 2016/1/25.
 */
public class CodeServlet extends HttpServlet{

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("image/jpeg");
        response.setHeader("Cache-Control", "no-cache");
        response.setHeader("Pragma", "No-cache");
        response.setDateHeader("Expires", 0L);
        int width = 70;
        int height = 30;
        BufferedImage image = new BufferedImage(width, height, 1);
        Graphics g = image.getGraphics();
        Random random = new Random();
        g.setColor(getRandColor(200, 250));
        g.fillRect(0, 0, width, height);
        g.setFont(new Font("Arial", 0, 25));
        g.setColor(getRandColor(160, 200));
        for (int i = 0; i < 155; i++) {
            int x = random.nextInt(width + 100);
            int y = random.nextInt(height + 100);
            int xl = random.nextInt(10);
            int yl = random.nextInt(12);
            g.drawOval(x, y, x + xl, y + yl);
        }
        String code = request.getParameter("code");
        String sRand = code;
        for (int i = 0; i < sRand.length(); i++) {
            String rand = sRand.substring(i, i + 1);
            g.setColor(new Color(20 + random.nextInt(110), 20 + random
                    .nextInt(110), 20 + random.nextInt(110)));
            g.drawString(rand, 14 * i + 5, 25);
        }
        g.dispose();
        javax.servlet.ServletOutputStream imageOut = response.getOutputStream();
        JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(imageOut);
        encoder.encode(image);
    }

    private Color getRandColor(int fc, int bc) {
        Random random = new Random();
        if (fc > 255)
            fc = 255;
        if (bc > 255)
            bc = 255;
        int r = fc + random.nextInt(bc - fc);
        int g = fc + random.nextInt(bc - fc);
        int b = fc + random.nextInt(bc - fc);
        return new Color(r, g, b);
    }
}
